Milling machine



April 25, 1939.v A. l.. KRAusE v MILLING MACZHINE Filed Aug. 18,1957 5 sheets-#sheet 1 April 25, 1939; l.;K'RAusI-z` n 2,155,864

K 'IL-LINGMACHINE f 'Filled Aug; 18;- `193'?, Y, s'sneets-sneet 2' Malik/Toe L i y y .YPEED Y Mm my Inventor Abril 25,1939. M ,KRAQSE T y 2,155,864

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Patented Apr. 25, 1939 PATENT' OFFICE y MILLING MACHINE y August L. Krause, Providence, R. I., assignor to Brown and Sharpe Manufacturing Company,

a. corporation of Rhode Island -Application August 18, 1937, Serial No. 159,699

14 Claims.

The present invention'relates to improvements in milling machines, and more particularly to improvements in automatic control means for effecting relative translatory movements between a milling cutter spindle and a work support and for driving the spindle.

It is a principal object of the present inventionk to provide in a machine of this description, driving and control means for the cutter spindle which is arranged to operate in conjunction with the table movement to yield a number of new and useful operating' cycles of the machine. in which oppositely faced cutters mounted on the spindle may be rendered operative selectively by a reversal of the spindle drive during the continued travel of the table in one direction to perform alternate conventional and hook milling operations upon work pieces spaced along the length of the table.

It is more specifically an object of the invention to provide means well adapted for controlling the operation of the work supporting table and associated cutter spindle when fitted with oppositely faced milling cutters to cause successive hook milling and conventional milling cuts to be taken alternately by one or the other of said milling cutters on work pieces supported toward opposite ends of the table in accordance with an automatic cycle which calls for the reversal of the cutter spindle during relativemovement of the cutter spindle from one work piece to the other whereby finish cuts of the same type will be effected on each workpiece to produce work of identical quality and finish.

It is a. further object of the invention to provide an electrical control system which is well adapted to yield a number of new and useful operatingcycles for the most efiicientuse of oppositely faced milling cutters in the performance of milling operations on the machine.

With these and other objectsin view, as may hereinafter appear, the several features of the invention consist in `the devices, combinations and arrangement of parts hereinafter described and claimed, which together with the advantages to be obtained thereby, will be readily understood by one skilled in the art from the following description taken in connection with the accompanying drawings, in which Fig. 1 is a view in front elevation of a milling machine, only vso much of the machine being shown as is believed necessary to illustrate the connection of the present invention therewith; Fig..2 is a detail plan view of the work table and cutter spindle,

illustrating particularly the disposition o'f the oppositely faced cutters and workpieces to be engaged thereby; Fig. 3 is a diagram disclosing one operating cycle of which applicants improved` machine is capable; Fig. 4 is an electrical diagram of the machine; and Fig. 5 is an 5 explanatory diagram illustrating in a simplified form the operating connections shown in Fig. 4.

The machine disclosed in the drawings as embodying in a preferred form the several features of the present invention, is of the general type 10 disclosed inthe patent to Bennett and Krause, No. 2,068,840, dated January26, 1937, and comprises a work table |20 supported for transverse movements on ways formed on a base |22, and a milling cutter spindle |24 rotatably mountedon a 15 carriage or spindle head |26 which is supported for vertical adjustment on a machine column |28 forming an integral unit with the base |22. ,The work table of the machine is driven by means of a reversible two-speed electric motor |29 illus- 20 trated in Figs. 4 and 5, through mechanical driving connections includinga fast-slow clutch which is shiftable to cause the table to be driven from the motoralternatively at a feed or traverse rate. These driving connections as generally 25 shown in Fig. 4 of the drawings, comprise'a slow feed gear train including the worm |30 continuously driven from the table motor through connections, not shown,l and worm gear |32 loosely supported to turn on a hollow driven shaft 30 |34, and a quick traverse gear train comprising the bevel driving gear |36 continuously driven .from the table motor through connections, not shown, and gear |38 loosely sleeved on the shaft |34. There is also rigidly keyed to the shaft |34, 35

n a fast-slow clutch member |40, which is shiftable between alternative driving positions in which the clutch sleeve |40 and Shaft |34 are positively driven from the feed worm gear |32, or from the fast traverse bevel gear |38. The shaft |34 is. 40 provided at its right hand end with a gear |42 which is operatively connected to drive the table. For controlling the position of the clutch, the shaft |34 has journalled therein a control shaft |44 which is connected at one end by means of a 45 bell-crank |46 and link |48 to the armature |50 of a solenoid |52. A compression spring |54 supported between a stationary member |56 and a collar |58 on the control shaft |44, tends normally to maintain the clutch member |40 in its 50 position to the left in engagement with the slow feed worm gear |32. The cutter spindle l|24 is driven from a reversible electric motor |59 Vand reduction gearing carried `on the head |26, as shown in dotted lines in Fig. 1 of the drawings. 55

e switch control elements operable either manually or' by means of table dogs to control the direction, rate of travel, and starting-and stopping of the table, together with additional controls which may be actuated either manually or inx combination with the table movements to control the starting .and stopping and the direction of rotation of the cutter spindle. A

In accordance with a principal feature of applicants invention, switch control devices are provided whichv may be readily controlled to reverse the spindle -rotation at an intermediate point in the travelof the table in either direction, and thereby to cause alternate conventional and hook milling operations in the same order to be performed on separate work pieces spaced along the length of the table in the path of each of said cutters. A

The electrical devices employed for controlling the direction of rotation of the spindle, include spindle reversing switch connections which are energized at each reversal in the direction of table travel, and ,an interlock associated therewith operative to effect said reversal of the,

spindle subsequent yto the table reversal, and only after a second pass ofthe operating' cutter over the work piece supported in operating position with relation thereto. l n

In the specic embodiment of the invention shown, the interlock referred to,' -``is controlled from the connections for stoppingthe spindle whenthe table is moved` at aqlllck traverse rate, so that, when the table'is again slowed to a feed rate, the spindle will bestarted in the opposite direction for operation upon a. second work piece supported inl position for engagement with a second oppositely yfaced cutter. l

As best shown in Fig.- V1 of the drawings, the table operating. controls include the manually operable fast left", -fast right, ffeed left, feed right, and "stopswitch' control buttons supported on the control post 2| 0 mounted on the machine'base |22 adjacent the front side of the. worky supporting table |20, together` with corresponding dog actuated control plungers 2|| for operating each of these switches mounted on. the rear side of the post2l0 as generally indicated in dotted lines in Fig.K 1. The plungers 2|| engage respectively with correspondingly designated table dogs adjustably supported vin a T-shaped slot 2 |2-formed onthe front side of the table |20. For enabling the table to .be driven at either of two feed rates, there are also provided at the rear side of the table, two vertically movable dog actuated plungers 2M and 2| 6 shown in dotted lines in Fig. l, and arranged to be operated by dogs such as that shown at 2|8 (Fig. 2) adjustably supported in a T-shaped slot 220 on the rear side of the table. The plungers 2 I4 and 2|6 operate to control the position of the mercury switch illustrated in the electrical diagram Figs. 4 and 5. 'I 'he downward movement of the plunger 2M serves to close the mercury switch contact 2-26'to drive the table at the relatively faster feed rate, whereas, the downward movement'of` the plunger 2li operates to close the mercury switch contact 2-21 to cause the table to be driven at the relatively lslower feed rate. Inasmuch as the mechanical connections, not here shown, for controlling the operation of the mercury switch, are fully described and illustrated in the patent to Graves and Bennett, No. 2,077,408, dated April 20, 1937, for Machine tools, andV form specifically no part of the present invention, no further description thereof is believed necessary.

The operation of the spindle motor |59 and cutter spindle |24 is controlled automatically during the operation of the table in accordance with the setting of a number of spindle control switches supported on a panel 222 on the .machine column |28 (see Fig. 1). These controls as set forth-in thecaptions on the panel 222, provide for alternative" continuous or intermittent operation of the. spindle, and further determine the direction of .spindle rotation during table travel in each direction. d

The construction and operation of the electrical connections for controlling the operation of the table and the cutter spindle respectively, vthrough their driving motors, will be briefly described in connection with the electrical wiring diagram Fig. 4, and the explanatory diagram Fig. 5, so far as necessary to make clear the connection therewith of the several new and patentable` features of construction and operation of the machine above set forth.

vThe table and cutter spindle motors are driven A vfrom a three-phase power line designated as `L|,

L2 and L3. The table motor is controlled by a reversing switch having two exciting relays L and R. The main switch for the'table motor is supported on a panel indicated in dotted lines at 226 (see Fig. 4), and comprises two sets of contacts which are controlled by the relay coils L and R respectively, to connect the motor and table for right hand or left hand operation. The high speed and low speed switches for the table motor are mounted on a second panel indicated at 228 in dotted lines, and comprises two sets of contacts controlled respectively by the relay coils HS or'LS for high speed or low speed operation of the table motor.

0n another panel indicated at 230 in dotted lines, are carried the main switch contacts for the spindle motor |29 controlled by means of two relay coils SF and SR for opposite directions of rotation of the motor and spindle driven thereby. It will be noted that the several cutter spindle control switches operated by the control knobs on the panel 222, are illustrated in the electrical diagram Fig. '4, in their proper positions with relation to the panel 222 indicated in dotted lines.

On another panel indicated at 232 in dotted lines, are a number of secondary relay switches which are arranged to contol the operation of the table and spindle switches above described, together with the solenoid |50 which operates the slow feed and quick traversevclutch |38. These secondary relays comprise the secondary coils LR and RR controlled respectively by the feed-left and feed right table switches, the coils TL and TR controlled respectively by the"fast left" and fastright table switches, the secondary relay coil RC which controls the operation of the slow feed and quick traverse clutch solenoid |50, and two additional relays TLI 'and TRI which are connected in parallel with the relays 'zoV ` \present invention;v interlocking switch connect tions are providedwhich'are controlled by the spindle Amotor directional switch relays -SF and SR Whichoperate independently of a change in spindle motor in operation-in the -same direction until the circuit' toboth of these relays-is broken by a shift. in the rate of table travel from 25 tion, in which successive rough hook millingand b yfa milling cutter 240 upon a. work piece 2 42- mounted toward the left hand end of'thework-gi` supportingtable |20, and ,in whichA successivev 30 rough hook milling-and nishconventional millc ling cuts are taken` by an oppositely faced 'cutteijf I 246- on al similarwork piece 248 supported toward x the rlght'hand end of the table |20. Assiun'ing feed to quick traverse takesv place. When the table is again slowed to the feed rate, the solenoid 5 SF or SR is energized to drive thespindle motor in the direction whichis now determined in acthe panel 222 corresponding to the direction` in 1 20 which thetable is travelling. The interlock .re-V

ferred to, is provided by SF contact 3 |-435 and SR contact -3|--35,. f l l' Figs. 2 and 3 of the drawings, illustrate a. s'etup of applicants machine for automatic jopera` nish conventional milling cuts are performed that the table isJ started from :tn-intermediate the "fast right button, causing the tableto m at a vquick traverse rate vto -the rightu' starting the cutter spindle rotating in a counterclockwise directionto perform a hook` milling opof the work pieceV 242,- the.'reversing feed dog 252 actuates the feed left. switch 'to reverse' the direction. of table travel. 'The cutterspindle |24 is continued in operation-Inga. counterclocking cut is now performed on the work piece 242.

When this cut is completed, the`, fast left dog rate until again `slowed to a feed frate by engagement of the "feed left" dog 256` with the 'table' fee'd left button. The. cutter spindleis -c o now automatically startedin a clockwise direction, causing the cutter 246 to perform-a rough hook milling operation upon the work piece248. As-the cutter 246 -reachesl the shouldered end-of the work piece 248, afeed Areversing dog 258 5 eetates the "feed right button to reverse the direction of tab1e-travel from left to rig-ht without, however, reversing the cutter spindle which continues its operation in'a: clockwise direction to perform a second nish conventional milling 0 cuton the work piece 248; At the completion of" this operation upon the work piece 248, `a quick traverse rate dog 260` actuates the table yfast wise direction, so that a finishvconventionalmill-rthe `SRV `interlocking contact 3|.-35.v eration is possible due to the overlapping .action i operation above outlined, the table may be mainpiece. 1 It will be understood that the automatic cycle above described, Vis only one example of an automatic cycle which may be employed to adthe Vdirectionof table travel' to maintain the'.

vantage 'with applicants improved vdriving and co'ntrolsystem for the machine, and that variations in this cycle `m'ayV be readily made to accomodate different classes of work in which it is 7 'I'he'operation of, the electrical connections to |40 to quick traverse pc'isitiori.y i

Itis :assumed that the spindle intermittentcontinuous switch is set for intermittent opera- 5 position, as shown in Fig. 2, theroperator presses ove e as( the cutter 240 approaches theY workpiece .242,A

the feed'dog 250 actuates the feed'rig'l'itfswitch I to slow the table to a feed rate, at the Sametime tion, the spindle direction table' right switch isset for counterclockwise operation of the vspindle, and the spindle direction table left switch is set for clockwise spindle operation.

While the table continues in fast traverse to the right, the spindle motor is'prevented from star-ting because the contacts RC 2-30 land TRI 2.-20 are held open. As the feedA dog 250 now op- ".eratesf toV close contact 2'-|2,' contact |5||z` is opened, cle-energizing. TR and T Rl relays, but

leaving` the relay RR energized.v Contacts RC 2-30an'd TRI 2-29 close, thus establishing a circuit through RR contact 30--3I which remains closed andthe directional switch contact 3|;14

to energize the-spindle motor relay SR, thus starting 'the motor in a counterclockwise direction.

.When the roughingcut on the work piece 242 is completed, the table feed reverse dog 252 operates the feed left switch, closing contact 2-1 v cause' the machine to operate in accordance with 4 the automatic cycle above described, may be "-brieyfdescribed as followszf .When the operfatorpressesthe ffast right button, relays TR,

` TR| and RR are-'energized and held in by holdand opening contact |0-|| so that LR-is eneri y When reversal takesk place as above described,

without shifting the table .controls from the feed to quick traverse rate, the spindle motor relay I SR remains energized through the'operation of of relays LR and RR, which causes LR contact 30-35 to 'be'closedbefore RR contact 30-3I is opened. Upon completion of the finishing cut, the fast traverse` left dog 254 operates to close the This opspindle. The SR interlock 3I-35 opens, so that when the spindle motor is subsequently started, the direction thereof will be controlled by the setting of the spindle direction table left" switch.

As the table travelling at a quick traverse rate to the left, reaches a'position in which the cutter 246 is brought into operative relation to the work piece 248, the feed lef dog 286 acts upon the feed left switch to close the feed left contact 2-1 and to open contact III-4l, thus de-energizing TL and TLI. The opening of contacts TL 22-2I and 2I20 operates to deener gize the relays CR and CRI to shift the clutch 240 to feed position. Contacts TLI IS--Sl and RC 2 3! close, completing the circuit through the LR contact 30--35 and the "spindle direction table left switch contacts 35--12, thus energizing the spindle motor relay SF and causing the spindle to start rotating in a clockwise direction. SF interlock SI-SS closes, operating as above described to maintain the -spindle switch relay SF in operation when the direction of table travel is reversed, and until the spindle rotation is again stopped by the shift from feed to quick traverse rate. The operation of the electrical connections to reverse the direction of table drive' from left to right, and thereafter to subsequently shift the table to quick traverse right, are identical with the same operations above described in connection with the reversal at the other end of the table, and it is believed, therefore, need not be further described.

A modification of the automatic cycle above described, may be readily obtained, in which the two milling cuts on the work pieces located at each end of the table, may be performed at different feeding rates. To this end, the table dogs ZI'I, 2|8 and 2|9 are adjustably mounted on the back side of the table, as best shown in Figs. 1 and 2 of the drawings, for engagement with the fast feed and slow feed plungers 2H and 2I6, Y

which act through a mercuryswitch to energize respectively the switch ontactors IS .or HS for effecting slowfeed or fast feed operation of the table motor. These dogs, as illustrated in Figs. 1 and 2, are set to cause a rough milling cut on each work piece to be performed at a relatively slow rate, and the return finish conventional milling cut to be performed at the faster rate. As the table is started in operation to the right, the dog 2| 8 will have engaged with the slow feed plunger 2I6, causing the mercury switch to be shifted to the position shown in Fig, 5, in which the mercury switch contact 2-28 is closed. The table motor at this time continues in operation at the faster rate suitable for fast traverse of the table because contact RC 2-21 remains closed. When the table is now slowed to the feed rate by the actuation of the feed right switch by feed dog 250, contact RC 2-21 opens, and Contact RC 28-26 closes, de-energizing the coil HS and energizing LS, so that the table motor operates at the slower feed rate. At the instant of reversal of the table, dog 2I1 engages the fast rfeed plunger 2 I4 to shift the position of the merbe driven at the slower feed rate. At the instant of reversal of the table from left to right, the dog 2l! acts upon the fast feed plunger 2M to` again reverse the position of the mercury switch, opening contact 2-28 and closing contact 2--21 to deenergize LS and to energize HS for the return conventional milling cut upon the work piece 248 at the slower feed rate.

It will be understood that the invention is not limited to the specific embodiment shown, and that various deviations may be made therefrom without departing from the spirit and scope of the appended claims. Y

What is claimed is:

1. A milling machine having, in combination, a work table, a reversible drive for the table. table actuated feed and traverse directional control Aelements for said drive, a rotary cutter spindle adapted for supporting oppositely faced cutters thereon, a reversible drive for the spindle, and connections controlled by said control elements effective upon a shift from traverse to feed following table reversal at a feed rate. to reverse the spindle drive.

2. A milling machine having, in combination, a work table, a rotary cutter spindle adapted for supporting oppositely faced cutters thereon, a support for the spindle, means for effecting relative translatory movements to the work table and spindle support, feed and traverse directional control elements for'effecting said translatory movements in accordance with an automatic cycle comprising feed and return feed movements toward each limit of ,translatory movement and quick traverse movements therebetween, a reversible drive for the spindle, and devices actuated by said feed and traverse directional controls for reversing the spindle drive operative to cause a rotation of the spindle in one direction during one of said feed and return movements and in the other direction during the other of said feed and return movements.

3. A milling machine having, in combination, a work table, a reversible drive for the table and control devices therefor operative to effect a feed movement at a predetermined rate and a return feed movement at a different rate toward and from each limit of table movement, means controlled from the table for reversing the spindle at an intermediate point of the table travel in each direction, and thereby to cause one of said cutters by rotating in one direction to make successive second piece suitably supported on the table during continued travel of the table in the opposite direction at said first feed rate and the return movement thereof at said differentfeed rate.

4. A milling machine having, in combination, a work table, means for driving the table including means for reversing the direction of table drive and rate changing means operable to drive the table alternatively at feed and traverse rates, a rotary cutter spindle adapted to support oppositely faced cutters thereon, means for starting and stopping and reversing the direction of spindle rotation, and devices for controlling the operation of the table and spindle in accordance with an automatic cycle comprising feed, reverse feed and quick traverse, table actuated controls for imparting table feed and return feed infovez" and reversing means for the spindle comprismenis. fremeed. positions-.toward the :limit`- of table-'travel inzeeehvzdileeiien, and quekiraverse evementeoi the tabie--beifweea-sais feed posioris, Yand means. contrldby said table-actuated Cmolfor'l (1g-ming; the spindlein. one `direction during one of-,said fiables-.feed andrei-,urn feed movements -`and .in the .opposite direction gduring -theothercf said table Afeedand return-,feed move- :menta and for-st cppingzfthe spindle'krotationduring movement ofthetablegat quick traverse. 1

5;v A millingmachinehaving, in-'cnmbinatiemfa work table, means .fordriving the, tablejincluding means for reversingA the .direotior1- of. tableA drive and; rate changing means operable to drive the table alternatively at asfeed ,or traverseifa-tege. rotarycutter -spindle adapted-to support` oppositely faced cutters thereon, .a reversible, dri-ve;v for the spindle, means,` controlled by said; table1= drive reversing means for ,reversing-fthe direction of spindle 1 drive, an interlock operable: tog prevent reversal of the spindle drive, and means controlled by; said ratechangingV means togdisengagegthe interlock simultaneously with a shift from feedto traverse.`

6. A milling machine having, in combination, a work table, a reversible table drive, a rotary cutter spindle adapted to support oppositely faced cutters thereon, a reversible drive for the table, independent control devices for determining the direction of spindle rotation during table travel in each direction, and an interlock whereby either of said control devices 4is effective to maintain spindle rotation in the same direction during and Subscquent to reversal of the table, and means to disengage the interlock and thereby to shift the control of spindle rotation to the other of said devices.

7. A milling machine having, in combination, a work table, means for driving the table including means for reversingv the direction of table drive Y and rate changing means operable to drive the table alternatively at a feed or traverse rate,'a rotary cutter spindle adapted to support oppositely faced cutters thereon, means for starting and stopping and reversing the direction of spindle rotation, table actuated control means for determining the direction and rate of table travel, said table control means being constructed and arranged to reverse the spindle drive with each reversal in the direction of table travel, and an interlocking device operative toeffect said reversal of the spindle subsequent to the table reversal and only upon a shift in the rate of table travel from traverse to feed.

interlock during the return movement of the table n subsequent to each reversal.

9. A milling machine having, in combination, a work table, a rotary cutter spindle adapted for supporting oppositely faced cutters thereon, electrical driving and reversing means for the table including left and right directional feed and traverse' switch connections, and electrical drivging'spindle.reversinggswiteh:connections actuated -fbyt'he. tabladireetionanseiten c onnectionsran interlockin spindle-reversing switch connee-,titles Operative@4 preventfreversai-of the spindle, en( epiridlefestertine-acd Stopping-:switch C0IiIiQnS- fillet 'from-said, table traverse switch` c :innectims to-stop the. spindle and` o disengage; the v. ir-1terlock and vby said,tablefeed switch: connections .tee-Start-:the epindlefin accord- 10..,Ami11ing machmehavinalmgcombination.

afwrk tablaarotary lcritter:spindle adapted :for supporting oppositely faced ,cutters thereon;- electrical drniving andreversing means for theetable gincluding left andi` right; directional." feed and traverse,j-svvitch-v connections; and: electricaladriving -and reversing, ineens for tliespind-le 'comprising independentgcontrolf switches forifdeterminspindle rotation in the. saine-direction; is' maintainedl Vfinderk the control aof` each ,one-nf saidindependent .control -;swit-CheS f1-n `turn:subsequent to table reversal, and means controlled by table movement to disengage the interlock.

11. A milling machine having, in combination, a work table, a rotary cutter spindle adapted for supporting oppositely faced cutters thereon, electrical driving and reversing means for the table including left and righti directional feed and traverse switch connections, and electrical driving and reversing means for the spindle compris'- ing starting and stopping switch connections oon-` trolled by the table feed switch connections to start the yspindle and by said traverse switch connections to stop the spindle,V spindle reversing switch connections actuated by saidtable directional switch connections to reverse the spindle,

l an interlock in said spindle reversing switch connections operative to prevent reversal of the spindle upon reversal of the table, and means effective upon stopping the spindle to disengage theinterlock.

12. A milling machine having, in combination, a. work table, a rotary cutter spindle adapted for supportingoppositely faced cutters thereon,l

. ing the direction of-spindle.' rotation during .table vtravel in --.eacl 1- dire ction-l--an interlock f whereby ble to effect a quick traverse movement of the f ytable in one direction followed by'feed and return feed movements at different rates, and to start the spindle rotating continuously in one direction for the performance of successive hook and conventional milling cuts by one of said cutters on a work piece suitably mounted on `the table, and thereafter tostop the spindle and to effect a quick traverse movement of the table in the reverse direction followed by continued feed and return feed movements at different rates, and to start the spindle continuously rotating in the opposite direction for the performance of successive hook and conventional milling cuts in the same order by the other of said cutters on a second work piece suitably mounted on the table.

13.. A milling machine having, in combination,

a work table, a rotary cutter spindle adapted for supporting oppositely faced cutters thereon,

a support for the spindle, means for eifecting relative translatory movements to the work table and spindle support, devices controlled from the table for effecting translatory movements-at variable feed and traverse rates in accordance with an automatic cycle comprising a predetermined rate of feed and a different rate of return feed movement to and from each Vlimit of translatory movement, and quicktraverse movements therebetween, a reversible drive for the spindle,

vand connections actuated by said table controlled devices for reversing the spindle' drive operative to cause the rotation of the spindle in one direc-- tion during one of said feed and return feed movements, and in the other direction during the other of said feed and returnfeed movements.

14. Amilling machine having, in combination, a movable work table, a rotary cutter spindle adapted to support two oppositely faced milling cutters, driving connections for the table including a. variable speed motor, and including rate changing means operable to drive the table alternatively at feed and traverse rates, driving connections for the spindle including a reversible 'spindle motor, and devices forv controlling` the operation of the table and spindle in accordance with an automatic cycle comprising directional lfeed and quick traverse table actuated controls for imparted feed and return feed movements to the table from feed positions toward the limit of table travel in each direction, and quicktraverse movement to the table between said feed positions, subsidiary switch connections controlled by said tableactuated controls for driving the spindle in one direction during one of said table feed 

